Titanium based product and method for manufacturing the same

ABSTRACT

A method for manufacturing a titanium based product includes the following steps. The first step is providing a titanium hydride ingot. The next step is pre-sintering the titanium hydride ingot to dehydrogenate the titanium hydride ingot according to a first temperature control mode, so as to form a titanium ingot. The next step is machining the titanium ingot to form a titanium semi-product having a desired shape. The last step is post-sintering the titanium semi-product according to a second temperature control mode that is different from the first temperature control mode, so as to form the titanium based product.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of priority to Taiwan PatentApplication No. 107129622, filed on Aug. 24, 2018. The entire content ofthe above identified application is incorporated herein by reference.

Some references, which may include patents, patent applications andvarious publications, may be cited and discussed in the description ofthis disclosure. The citation and/or discussion of such references isprovided merely to clarify the description of the present disclosure andis not an admission that any such reference is “prior art” to thedisclosure described herein. All references cited and discussed in thisspecification are incorporated herein by reference in their entiretiesand to the same extent as if each reference was individuallyincorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a titanium based product and a methodfor manufacturing the same, and more particularly to a two-stagesintered titanium based product and a method for manufacturing the same.

BACKGROUND OF THE DISCLOSURE

Titanium and its alloys have many advantages such as stable chemicalproperties, high strength, low weight, high temperature resistance, highcorrosion resistance, and high biocompatibility. In recent years, theapplication industries of titanium alloys widely include automobile,ship, medicine, entertainment equipment, and mobile electronic device.

The main methods for shaping titanium and its alloys include casting,forging and powder metallurgy. Although the casting and forging methodshave simpler operations, it is difficult to produce products havingcomplex structures and shapes therewith, and the products producedthereby may have poor precision. The powder metallurgy method is atechnique that uses a powder material to form a metal product by shapingand sintering. In contrast, the powder metallurgy method can solveshaping problems associated with components with complex shapes.However, the conventional powder metallurgy method is provided with onlyone sintering step for the formation of the titanium or titanium alloymaterial. The one-stage sintered titanium or titanium alloy material isdifficult to be precisely processed. In addition, the equipment used toprocess the one-stage sintered titanium or titanium alloy material mayhave a high wear rate and thus result in a high processing cost.

Therefore, there is an urgent need to reduce the processing difficultyand cost of the titanium and titanium alloy products having requiredmechanical properties.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the presentdisclosure provides a method for manufacturing a titanium based product,which can overcome the problems associated with the shaping of titaniumor titanium alloy products, and a titanium based product manufactured bythe method.

In one aspect, the present disclosure provides a method formanufacturing a titanium based product, including: providing a titaniumhydride ingot; pre-sintering the titanium hydride ingot to dehydrogenatethe titanium hydride ingot according to a first temperature controlmode, so as to form a titanium ingot; machining the titanium ingot toform a titanium semi-product having a desired shape; and post-sinteringthe titanium semi-product according to a second temperature control modethat is different from the first temperature control mode, so as to formthe titanium based product.

In one aspect, the present disclosure provides a titanium based productmanufactured by the aforesaid method. The titanium based product has aVickers hardness between 200 HV and 250 HV, a tensile strength between600 MPa and 650 MPa, and a yield strength between 500 MPa and 550 MPa.

One of the advantages of the present disclosure is that the method ofthe present disclosure, which pre-sinters the titanium hydride ingotaccording to a first temperature control mode, then machines thetitanium ingot formed, and subsequently post-sinters the titaniumsemi-product according to a second temperature control mode formed, canreduce the wear rate of the processing equipment, thereby reducing thecost.

These and other aspects of the present disclosure will become apparentfrom the following description of the embodiment taken in conjunctionwith the following drawings and their captions, although variations andmodifications therein may be affected without departing from the spiritand scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thefollowing detailed description and accompanying drawings.

FIG. 1 is a flowchart of a method for manufacturing a titanium basedproduct of the present disclosure.

FIG. 2 is a schematic view illustrating a step S1 of the method formanufacturing a titanium based product of the present disclosure.

FIG. 3 is a schematic view illustrating a step S2 of the method formanufacturing a titanium based product of the present disclosure.

FIG. 4 is a schematic view illustrating a step S3 of the method formanufacturing a titanium based product of the present disclosure.

FIGS. 5 and 6 are schematic views illustrating a step S4 of the methodfor manufacturing a titanium based product of the present disclosure.

FIG. 7 is a schematic view illustrating a step S5 of the method formanufacturing a titanium based product of the present disclosure.

FIG. 8 shows a first temperature control mode used in the step S2 of themethod for manufacturing a titanium based product of the presentdisclosure.

FIG. 9 shows a second temperature control mode used in the step S4 ofthe method for manufacturing a titanium based product of the presentdisclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure is more particularly described in the followingexamples that are intended as illustrative only since numerousmodifications and variations therein will be apparent to those skilledin the art. Like numbers in the drawings indicate like componentsthroughout the views. As used in the description herein and throughoutthe claims that follow, unless the context clearly dictates otherwise,the meaning of “a”, “an”, and “the” includes plural reference, and themeaning of “in” includes “in” and “on”. Titles or subtitles can be usedherein for the convenience of a reader, which shall have no influence onthe scope of the present disclosure.

The terms used herein generally have their ordinary meanings in the art.In the case of conflict, the present document, including any definitionsgiven herein, will prevail. The same thing can be expressed in more thanone way. Alternative language and synonyms can be used for any term(s)discussed herein, and no special significance is to be placed uponwhether a term is elaborated or discussed herein. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termsis illustrative only, and in no way limits the scope and meaning of thepresent disclosure or of any exemplified term. Likewise, the presentdisclosure is not limited to various embodiments given herein. Numberingterms such as “first”, “second” or “third” can be used to describevarious components, signals or the like, which are for distinguishingone component/signal from another one only, and are not intended to, norshould be construed to impose any substantive limitations on thecomponents, signals or the like.

Referring to FIG. 1, which is to be read in conjunction with FIGS. 2 to6, the present disclosure provides a method for manufacturing a titaniumbased product including the following steps. The first step (i.e., stepS1) is providing a titanium hydride ingot. The next step (i.e., step S2)is pre-sintering the titanium hydride ingot according to a firsttemperature control mode to form a titanium ingot. The next step (i.e.,step S3) is machining the titanium ingot to form a titanium semi-producthaving a desired shape. The last step (i.e., step S4) is post-sinteringthe titanium semi-product to form a titanium based product. The titaniumbased product can be a casing or component of an electronic device, butis not limited thereto.

Reference is made to FIG. 2, in the step S1, the titanium hydride ingot102 can be formed from a titanium hydride powder 100. Specificallyspeaking, the titanium hydride powder 100 can have a predeterminedparticle size, and can be put into a specific mold and dry-pressed at asuitable pressure to form the titanium hydride ingot 102 with a specificshape and size. According to particular requirements, a predeterminedamount of other metal (e.g., aluminum and vanadium) or metal precursorpowders can be mixed into the titanium hydride powder 100.

In the present embodiment, the titanium hydride powder has an averageparticle size between 3 μm and 500 μm, and preferably between 100 μm and300 μm. If the average particle size is less than 1 μm, the titaniumhydride powder may spontaneously ignite. If the average particle size isgreater than 400 μm, the titanium hydride powder is difficult to bedensely pressed, so that the titanium hydride ingot 102 does not have arequired density.

The titanium hydride powder can be made by the following steps. Firstly,a titanium sponge is hydrogenated under a vacuum condition and anatmosphere of a substantially pure hydrogen gas (purity >99.9%) to forma titanium hydride sponge. The titanium sponge is preferably azero-order titanium sponge that has a low oxygen-content. Subsequently,the titanium hydride sponge is crushed by being ball-milled under aprotective atmosphere, and the titanium hydride particles thus obtainedare classified by particle size.

Reference is made to FIG. 3, in the step S2, the titanium hydride ingot102 is placed in a chamber of a sintering device and the chamber ismaintained at a vacuum degree of about 2×10⁻⁴ torr by pumping.Subsequently, the titanium hydride ingot 102 is pre-sintered (i.e.,sintered for the first time) according to a first temperature controlmode. During this process, the titanium hydride ingot 102 isdehydrogenated to form a high-purity titanium ingot 104. That is to say,a dehydrogenation reaction of the titanium hydride ingot 102 is carriedout during this process. In other embodiments, the titanium hydrideingot 102 can be pre-sintered to form a sintered body, and the sinteredbody can proceed to be dehydrogenated under a vacuum condition.

As shown in FIG. 8, the first temperature control mode is exemplified asgradually increasing a pre-sintering temperature up to 800-900° C. at apredetermined heating rate, then maintaining the pre-sinteringtemperature for 3 hours, and finally cooling the pre-sinteringtemperature to the room temperature. In the present embodiment, thetitanium ingot 104 formed in the step S2 has a line shrinkage ratebetween 6% and 9% with respect to the titanium hydride ingot 102,preferably 8.5%, a density between 3.5 g/cm³ and 4.1 g/cm³, preferably3.71 g/cm³, a porosity between 15% and 20%, preferably 17.5%, and aVickers hardness between 90 HV and 110 HV, preferably 108 HV.

Reference is made to FIG. 4 which is to be read in conjunction with FIG.3, in the step S3, a machine tool (not numbered) such as a millingcutter can be used to change the shape and size of the titanium ingot104, so as to form a titanium semi-product 106 that corresponds in shapeand size to the final product before the post-sintering begins. However,the machine tool used in the step S3 is merely an example and is notmeant to limit the present disclosure. It should be noted that, thetitanium ingot 104 has a relatively low hardness and density, so thatthe wear rate of the processing equipment can be reduced, therebyreducing costs.

Reference is made to FIGS. 5 and 6, in the step S4, the titaniumsemi-product 106 is placed in a chamber of the sintering device and thechamber is maintained at a vacuum degree of about 2×10⁻⁴ torr bypumping. Subsequently, the titanium semi-product 106 is pre-sintered(i.e., sintered for the second time) according to a second temperaturecontrol mode that is different from the first temperature control mode,so as to form a titanium based product 108 having a high purity, highdensity and low oxygen content.

As shown in FIG. 9, the second temperature control mode is exemplifiedas gradually increasing a post-sintering temperature up to 1200-1300° C.at a predetermined heating rate, then maintaining the post-sinteringtemperature for 3 hours, and finally cooling the pre-sinteringtemperature to the room temperature. In the present embodiment, thetitanium based product 108 formed in the step S4 has a line shrinkagerate between 13% and 16% with respect to the titanium hydride ingot 102,preferably 14.5%, a density of about 4.45 g/cm³, a porosity of about0.4%, and a Vickers hardness between 200 HV and 250 HV, preferably 240HV.

It should be noted that, if predetermined amounts of other metal powderssuch as 6 wt % of an aluminum powder and 4 wt % of a vanadium powder aremixed into the titanium hydride powder 100 in the step S1, the titaniumbased product 108 obtained by the step S4 would contain other metalcomponents except for titanium.

Referring now to FIG. 1 along with FIG. 7, the method of the presentdisclosure can further include a step (step S5) of modifying anappearance of the titanium based product 108. In the present embodiment,surface trimming, polishing, lead angle chamfering processes, and etc.,can be performed on the titanium based product 108 to meet precisionrequirements in actual use. However, the aforesaid processes are merelyexamples and are not meant to limit the present disclosure. Aftermodifying the appearance of the titanium based product 108, the methodof the present disclosure can further include a step (step S6) ofprecisely machining the modified titanium based product 108. In thepresent embodiment, the modified titanium based product 108 can beformed with through holes H, but is not limited thereto, so as toincrease its structural complexity.

One of the advantages of the present disclosure is that the method ofthe present disclosure, which pre-sinters the titanium hydride ingotaccording to a first temperature control mode, then machines thetitanium ingot formed, and subsequently post-sinters the titaniumsemi-product according to a second temperature control mode formed, canreduce the wear rate of the processing equipment, thereby reducingcosts.

Furthermore, by using the aforesaid technical solution, the process timecan be reduced and the processing precision and structural complexity ofthe titanium based product can be increased.

In addition, the titanium based product of the present disclosure,compared with the conventional titanium substrate, has more excellentmechanical properties. The comparison between the titanium based productof the present disclosure and the commercial titanium substrates isshown in Table 1.

TABLE 1 Titanium based Ti Ti MIM Ti product Gr.3 Gr.4 BASF Vickershardness (HV) 240 150 165 160-240 Density (g/cm³) 4.45 4.51 4.51 >4.2tensile strength (MPa) 641 380 550 550 yield strength (MPa) 511 450 480480 ductility (%) 11 18 15 >5 elastic modulus (GPa) 105 105 105 105

As shown in Table 1, the titanium based product of the presentdisclosure, compared with the commercial titanium substrate, has animproved hardness, tensile strength, and yield strength. The tensilestrength of the titanium based product is between 600 MPa and 650 MPaand the yield strength of the titanium based product is between 500 MPaand 550 MPa.

The foregoing description of the exemplary embodiments of the disclosurehas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the disclosure to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the disclosure and their practical application so as toenable others skilled in the art to utilize the disclosure and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present disclosurepertains without departing from its spirit and scope.

What is claimed is:
 1. A method for manufacturing a titanium basedproduct, comprising: providing a titanium hydride ingot; pre-sinteringthe titanium hydride ingot to dehydrogenate the titanium hydride ingotaccording to a first temperature control mode, so as to form a titaniumingot; machining the titanium ingot to form a titanium semi-producthaving a desired shape; and post-sintering the titanium semi-productaccording to a second temperature control mode that is different fromthe first temperature control mode, so as to form the titanium basedproduct.
 2. The method according to claim 1, further comprisingmodifying an appearance of the titanium based product after the step ofpost-sintering the titanium semi-product.
 3. The method according toclaim 2, further comprising precisely machining the modified titaniumbased product after the step of modifying the appearance of the titaniumbased product.
 4. The method according to claim 1, wherein the step ofproviding the titanium hydride ingot includes dry-pressing a titaniumhydride powder to form the titanium hydride ingot.
 5. The methodaccording to claim 1, wherein the first temperature control mode isgradually increasing a pre-sintering temperature up to 800-900° C. at apredetermined heating rate and then maintaining the pre-sinteringtemperature for 3 hours.
 6. The method according to claim 5, wherein thesecond temperature control mode is gradually increasing a post-sinteringtemperature up to 1200-1300° C. at the predetermined heating rate andthen maintaining the post-sintering temperature for 3 hours.
 7. Themethod according to claim 6, wherein the predetermined heating rate is5° C./min.
 8. The method according to claim 1, wherein the titaniumingot has a line shrinkage rate between 6% and 9% with respect to thetitanium hydride ingot, and the titanium based product has a lineshrinkage rate between 13% and 16% with respect to the titanium hydrideingot.
 9. The method according to claim 1, wherein the titanium ingothas a density between 3.5 g/cm³ and 4.1 g/cm³, and the titanium basedproduct has a density of 4.45 g/cm³.
 10. The method according to claim1, wherein the titanium ingot has a porosity between 15% and 20%, andthe titanium based product has a porosity of 0.4%.
 11. The methodaccording to claim 1, wherein the titanium ingot has a Vickers hardnessbetween 90 HV and 110 HV, and the titanium based product has a Vickershardness between 200 HV and 250 HV.
 12. A titanium based productmanufactured by the method according to claim 1, the titanium basedproduct having a Vickers hardness between 200 HV and 250 HV, a tensilestrength between 600 MPa and 650 MPa, and a yield strength between 500MPa and 550 MPa.